Tubing bending machine

ABSTRACT

A tubing bending machine comprising a bending assembly further comprising a hydraulic cylinder which reciprocates a plurality of bands set apart by guide discs, with each band being held in place by a forming die having two threaded ends which are secured to the hydraulic cylinder by means of nuts. The bending assembly is mounted vertically in a frame, on which two tubing guides are also mounted by means of bearings. The tubing guides have alignment guides corresponding to each band on the bending assembly and are oriented such that when a piece of tubing inserted in the machine is resting on the tubing guide, the piece of tubing will be aligned with a corresponding band and forming die.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not Applicable.

REFERENCE TO “MICROFICHE APPENDIX”

[0003] Not Applicable.

BACKGROUND OF THE INVENTION

[0004] This Invention relates to a device and method for bending metal tubing, particularly square or rectangular metal tubing. Bending metal tubing is desired in, for example, construction of the framework of prefabricated buildings to form curved structures, alleviating the need for preparing joints between more than one piece of tubing. The desired method to bend tubing in the present invention is to press the tubing in a semicircular press which not only bends the tubing, but simultaneously swages the tubing with a depression on the inside of the bend. This press is capable of introducing a bend of up to 180 degrees. By using a plurality of bending dies mounted in parallel, several pieces of tubing may be bent identically at the same time, resulting in a substantial saving of time and in uniformity of bend between the individual pieces of tubing.

SUMMARY OF THE INVENTION

[0005] The present Invention involves a method and device for simultaneously bending multiple pieces of tubing through the use of a hydraulically actuated bending assembly which includes a plurality of bands set apart by spacing disks. Each band is accompanied by a corresponding forming die, which is mounted around the circumference of the band. This bending assembly is mounted beneath a hydraulic piston that is mounted in a frame vertically above the tubing to be bent. The tubing is inserted into the machine and is supported on each end of the desired shape by a tubing guide, which is supported by a bearing on each end and includes alignment guides to ensure that each piece of tubing is appropriately aligned with its corresponding bending die. As the bending assembly is forced down against the tubing by the hydraulic piston, the tubing is bent by the bending assembly and is simultaneously swaged on the inside of the bend by the swaging die.

DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is an oblique view of the machine in its entirety.

[0007]FIG. 2 is an end view of the machine showing pieces of tubing inserted beneath the bending assembly.

[0008]FIG. 3 is a top view of the machine showing the bending assembly above pieces of tubing.

[0009]FIG. 4 is a side view of the machine showing the bending assembly above pieces of tubing and showing the bearings on the tubing guides.

[0010]FIG. 5 is a side view of the machine with the bending assembly in the depressed position.

[0011]FIG. 6 is a cutaway view of a portion of the machine showing the position of one of the tubing guides with the bending assembly in the depressed position.

[0012]FIG. 7 is a side view of the machine with the bending assembly retracted after being depressed.

[0013]FIG. 8 is a cutaway view of a portion of the machine showing the position of one of the tubing guides after the bending assembly has been retracted.

DETAILED DESCRIPTION OF THE INVENTION

[0014]FIG. 1 is an oblique view of the preferred embodiment of the machine comprising the Invention. FIG. 2 is an end view of the machine, showing five pieces of tubing 12 having been inserted into the machine beneath the bending assembly 10. The bending assembly 10 is shown to further comprise a series of bands 20 separated by guide discs 16, with each band 20 held in place by a forming die 22. Each forming die has two threaded ends 28 which are secured to a hydraulic cylinder 18 by means of nuts 30. This entire bending assembly 10 is mounted vertically in the frame 40 with the hydraulic cylinder 18 oriented to reciprocate downwards. These details of the bending assembly 10 may also be seen in FIGS. 3, 4, 5, and 7.

[0015] Referring to FIGS. 1, 2, and 3, there are two tubing guides 14 mounted to the frame 40 on either end of the bending assembly 10. Each tubing guide 14 is mounted to the frame 40 by means of bearings 24 which are connected to the ends of the tubing guides 14 and to a mounting bracket 42. The mounting brackets 42 are connected directly to the frame 40. Each tubing guide 14 has a plurality of alignment guides 26 which ensure that each piece of tubing inserted into the machine is properly aligned with the corresponding band 20 and forming die 22.

[0016] Referring to FIG. 2, it may be seen that there are positions for bending five pieces of tubing at one time. It is understood that by adding guide discs, bands, and forming dies, more pieces of tubing may be bent at one time, with no theoretical limit. Fewer pieces may be bent by merely not placing tubing in some of the positions. It is further understood that the preferred embodiment of the machine will have an odd number of positions so that any number of tubes from one to the maximum capacity of the machine may be bent without causing the machine to overbalance to either side.

[0017] Referring to FIG. 5, one can see the bending assembly 10 in its depressed position as well as the pieces of tubing 12 having been bent. Referring to FIG. 6, as the bending assembly 10 is depressed and the pieces of tubing 12 are bent, the tubing guides 14 rotate about their bearings 24 to maintain their support of the pieces of tubing 12. At this time, as the bending assembly is depressed, the forming dies 22 swage a shaped groove (not depicted) on the inside radius of the bend in the pieces of tubing 12. This shaped groove assists in the bending process and adds mechanical strength to the curved portion of the finished, bent pieces of tubing 12. Without this shaped groove, the resulting bent tubing would have certain structural weaknesses that would otherwise occur. Referring to FIGS. 7 and 8, as the bending assembly 10 is retracted back to its initial position, the pieces of tubing 12 retain their bent shape and the tubing guides 14 become free to rotate back to their initial position.

[0018] While the figures depict the guide discs 16, bands 20, and forming dies 22 as having a smooth arc, it is also understood that this shape may be varied as needed to produce a particular desired shape in the bent tubing. It is emphasized that the guide discs 16 constitute a major structural element of the bending assembly 10 and that by projecting beyond the bands 20 and forming dies 22, they provide a guide to prevent the tubing 12 from twisting or otherwise becoming misshapen. FIGS. 9 and 10 shows a detail of the band 20 and die 22 with the threaded ends 28 as well as the relationship of these elements in contact with a piece of tubing 12.

[0019] Enormous forces are necessary to bend and swage the tubing 12. Although it has not been described in detail, persons with ordinary skill aware of the forces required understand the necessity for powerful hydraulic cylinders as well as sturdy frames and mounting brackets. Those with ordinary skill in the art will understand the making of the various parts forming the complete machine, including the mounting of the hydraulic cylinder 18 to reciprocate the bending assembly 10 and the support and foundation for mounting the tubing guides 14 to the bearings 24 and to the mounting brackets 42.

[0020] Catalogue of Elements CATALOGUE OF ELEMENTS 10 Bending Assembly 12 Tubing 14 Tubing Guide 16 Guide Discs 18 Hydraulic Cylinder 20 Bands 22 Forming Dies 24 Bearings 26 Alignment Guides 28 Threaded Ends 30 Nuts 40 Frame 42 Mounting Brackets 

The invention claimed is:
 1. A method of bending metal tubing comprising: a. aligning a piece of tubing lengthwise with a forming die; and b. hydraulically pressing said forming die against said tubing.
 2. A tubing bending machine comprising: a. a frame; b. a bending assembly mounted vertically in said frame, with said bending assembly further comprising: i. hydraulic means for reciprocating said bending assembly; ii. a plurality of guide discs arranged parallel to each other and mounted to said hydraulic means, with a corresponding plurality of bands between said guide discs; and iii. a plurality of forming dies equal in number to said plurality of bands, with each of said forming dies having two threaded ends, with one of said forming dies placed along the circumference of each of said bands, and with each forming die secured to said hydraulic means by a nut fastened on said threaded ends; and b. two tubing guides mounted to said frame below and at either end of said bending assembly, with each of said tubing guides mounted to said frame by means of a bearing at either end of said tubing guides, with said bearings attached to said frame by means of a mounting bracket.
 3. A bending assembly further comprising: a. hydraulic means for reciprocating said bending assembly; b. a plurality of guide discs arranged parallel to each other and mounted to said hydraulic means, with a corresponding plurality of bands between said guide discs; and c. a plurality of forming dies equal in number to said plurality of bands, with each of said forming dies having two threaded ends, with one of said forming dies placed along the circumference of each of said bands, and with each forming die secured to said hydraulic means by a nut fastened on said threaded ends. 